The Earth Observatory site
hosts a rich, deep archive of more than 12,000 interpreted satellite images covering a wide range of topics and locations. The archive includes images of natural events as well as more diverse featured images

Satellite images are like maps: they are full of useful and
interesting information, provided you have a key. They can show us how
much a city has changed, how well our crops are growing, where a fire is
burning, or when a storm is coming. To unlock the rich information in a
satellite image, you need to:

Determining scale

Looking for patterns, shapes, and textures

Reading colors (including shadows)

Finding north

These tips come from the Earth Observatory’s writers and
visualisers, who use them to interpret images daily. They help the user to get oriented enough to pull valuable information out of satellite
images.

1. Determining Scale

Some images from military or commercial satellites are detailed enough
to show local features. Such satellites zoom in on small areas to
collect fine details down to the scale of individual houses or cars. In
the process, they usually sacrifice the big picture.

Earth science
researchers typically want a wide-angle lens to see whole ecosystems or
atmospheric fronts. As a result, NASA images are less detailed but cover
a wider area, ranging from the landscape scale (185 kilometers across)
to an entire hemisphere. The level of detail depends on the satellite’s
spatial resolution (The width of each pixel is the
satellite’s spatial resolution). Commercial satellites have a spatial resolution down to 50
centimeters per pixel.

Before beginning to interpret an image, it helps to know what
the scale is. Does the image cover 1 kilometer or 100? What level of
detail is shown? Images published on the Earth Observatory include a
scale.You can learn different things at each scale. For example, when
tracking a flood, a detailed, high-resolution view will show which homes
and businesses are surrounded by water. The wider landscape view shows
which parts of the county or metropolitan area are flooded and perhaps
where the water is coming from. A broader view would show the entire
region—the flooded river system or the mountain ranges and valleys that
control the flow. A hemispheric view would show the movement of weather
systems connected to the floods.

GOES satellites offer a nearly full view of the Earth’s disk. This
image shows North and South America on September 14, 2013. (Image by
the NASA/NOAA GOES Project Science Office.)

2. Looking for patterns, shapes, and textures

Geographers are very good at finding
patterns. This skill is useful in interpreting satellite imagery because
distinctive patterns can be matched to external maps to identify key
features.Bodies of water—rivers, lakes, and oceans—are often the simplest features to identify because they tend to have unique shapes and they show up on maps.Other obvious patterns come from the way people use the land. Farms
usually have geometric shapes—circles or rectangles—that stand out
against the more random patterns seen in nature. When people cut down a
forest, the clearing is often square or has a series of herring-bone lines
that form along roads. A straight line anywhere in an image is almost
certainly human-made, and may be a road, a canal, or some kind of
boundary made visible by land use.

Straight lines and geometric shapes in this image of Reese,
Michigan, are a result of human land use. Roads cut diagonally across
the squares that define farm fields. (NASA Earth Observatory image by
Jesse Allen and Robert Simmon, using ALI data from the NASA EO-1 team.)

3. Reading Colors

The colors in an image will depend on what kind of light the
satellite instrument measured. True-color images use visible light—red,
green and blue wavelengths—so the colors are similar to what a person
would see from space. False-color images incorporate infrared light and
may take on unexpected colors.

Sediment colors the sea near the mouth of the
Zambezi River. The water grows darker offshore as the sediment
disperses. (NASA Earth Observatory images by Robert Simmon, using Landsat 8 data from the USGS Earth Explorer.)

3.1 Water

Water absorbs light, so it is usually black or dark blue. Sediment
reflects light and colors the water. When suspended sand or mud is
dense, the water looks brown. As the sediment disperses, the water’s
color changes to green and then blue. Shallow waters with sandy bottoms
can lead to a similar effect.Sunlight reflecting off the surface of the water makes the water
look gray, silver, or white. This phenomenon, known as sunglint, can highlight wave features or oil slicks, but it also masks the presence of sediment or phytoplankton.

3.2 Plants

Plants come in different shades of green, and those differences
show up in the true-color view from space. Grasslands tend to be pale
green, while forests are very dark green. Land used for agriculture is
often much brighter in tone than natural vegetation.In some locations (high and mid latitudes), plant color depends on
the season. Spring vegetation tends to be paler than dense summer
vegetation. Fall vegetation can be red, orange, yellow, and tan;
leafless and withered winter vegetation is brown. For these reasons, it
is helpful to know when the image was collected.

The forests covering the Great Smoky Mountains of the Southeastern
United States change colors from brown to green to orange to brown as
the seasons progress. (NASA images courtesy Jeff Schmaltz LANCE/EOSDIS MODIS Rapid Response Team, GSFC.)

3.4 Cities

Densely built areas are typically silver or gray from the
concentration of concrete and other building materials. Some cities have
a more brown or red tone depending on the materials used for rooftops.

The contrast between Warsaw’s modern and historic neighborhoods is
easily visible by satellite. The new Stadion Narodowy is brilliant
white. Śródmieście (Inner City) was rebuilt after World War II and most
areas appear beige or gray. But some neighborhoods rebuilt with
older-style buildings, such as the red tile and green copper roofs of
Stare Miasto (Old Town). (Image courtesy NASA/USGS Landsat.)

3.5 Atmosphere

Clouds are white and gray, and they tend to have texture just as they do when viewed from the ground. They also cast dark shadows on the ground that mirror the shape of the cloud. Some high, thin clouds are detectable only by the shadow they cast.Smoke is often smoother than clouds and ranges in color from brown to gray. Smoke from oil fires
is black. Haze is usually featureless and pale gray or a dingy white.
Dense haze is opaque, but you can see through thinner haze. The color of
smoke or haze usually reflects the amount of moisture and chemical
pollutants, but it’s not always possible to tell the difference between
haze and fog in a visual interpretation of a satellite image. White haze
may be natural fog, but it may also be pollution.

Clouds, fog, haze and snow are sometimes difficult to distinguish
in satellite imagery, as in this MODIS image of the Himalaya from
November 1, 2013. (Image adapted from MODIS Worldview.)

Dust ranges in color, depending on its source. It is most often
slightly tan, but like soil, can be white, red, dark brown, and even
black due to different mineral content.Volcanic plumes also vary in appearance, depending on the type of eruption. Plumes of steam and gas are white. Ash plumes are brown. Resuspended volcanic ash is also brown.

4. Finding North

When you get lost, the simplest way to figure out where you are is
to find a familiar landmark and orient yourself with respect to it. The
same technique applies to satellite images. If you know where north is,
you can figure out if that mountain range is running north to south or
east to west, or if a city is on the east side of the river or the west.
These details can help you match the features to a map. On the Earth
Observatory, most images are oriented so that north is up. All images
include a north arrow.

The Australian Curriculum: Geography concept that seems to be the one causing most concerns for teachers is that of Scale. In previous Spatialworlds postings I explored the concept of scale and discussed the idea of looking at scale like a zoom tool. That is, as 21st Century citizens we zoom in and out of the spatial levels as we think about geographical events, phenomena and processes. One minute we may be thinking at the spatial level of global, then regional, then national and then local (not necessarily in that order). We repeatedly zoom in and out as we try to make sense of our world in geographical terms. This has not always been the case in the past, with citizens being much more locally focussed without access to travel, education and media that allow a broader perception of scale. It can be argued that there is a difference in scale perception between rural and city dwellers, less developed and more developed countries and between isolated and less isolated places. Certainly food for thought as we consider world views on a range of issues. Basically the creation of a map at a particular scale is simply a snapshot of where we are thinking at the time - if thinking global we create a map of the world at the appropriate scale.This posting gives a few ideas on practical ways to get the concept across to students (and teachers), delves into the terms small and large scale maps and discusses skill development in the Australian Curriculum: Geography.Some hands-on ideas

A point of scale which often causes consternation is the question of what is a small scale map versus a large scale map? To help with this it is best to just say that the smallest scale map is the globe (RF of 1: 40 million) - shows a large all of the world at little detail. Every map of a lesser ratio in number is called a large scale map - shows a smaller area of the earth in greater detail i.e. a 1:100 000 map is a smaller scale map that a 1:50 000 map. Just think 'globe small, 'globe small'!! ... and then work backwards from there to the largest scale maps of the local area.

Scale in the skills strand of the Australian Curriculum: GeographyAn understanding of scale is seen throughout the Inquiry and Skills strand of the Australian Curriculum: Geography. From representations of globes and maps in Foundation through to creating large and small scale maps conforming to cartographic conventions in Year 10 there is a progression of skills in relation to scale. The document below shows the progression of skills in the curriculum from F-10 - a well constructed learning progression involving the fundamental concept of scale.

ABC Splash is your go-to place for cutting-edge digital learning
experiences. Access selected ABC archives, contemporary shows and
interactive resources to help you teach and plan for the Australian
Curriculum.

The Choose your own statistics,
a dynamic resource produced in partnership with the Australian Human
Rights Commission. Use it with your middle years students to interrogate
data relating to a range of contemporary social issues.

This unique interactive learning resource has been designed to enable
students from Years 5 to 8 to gain a better understanding of important
human rights issues as they explore the latest statistics from respected
Australian institutions. Thought-provoking Infographics
encourage students to critically evaluate their beliefs and deepen their
understanding of the role that data representation plays in building
knowledge and influencing decisions about social issues. Innovative
technology enables students to explore the demographics of Australian
society on a national and state level and see how the constitution of
our country has changed over time. Through the exploration of
ten significant topics, students obtain a big picture overview of the
data behind current issues like homelessness, immigration, sexual
harassment, the justice system, and our ageing population. Interactive
graphs provide a snapshot of the cultural background, religious beliefs,
technology use and education and employment status of both Indigenous
and Non-Indigenous Australians of different ages and genders.
Statistics are presented using the full range of graphs included in the
syllabus requirements of the Australian Mathematics curriculum. Students
can customise and publish their own graphs, and all of the data is
available for download to Excel to enable further exploration.

ABC Splash contains over 300 geography resources for Foundation to year
10. This substantial range of video and audio clips investigates such
topics as global citizenship; renewable energy; the impact of tourism on
the Great Barrier Reef; the Mekong River; sustainable housing; and the
debate over land use in national parks.

Resources can be filtered by year level, subject, topic and media type
and are drawn from respected ABC programs such as Foreign Correspondent,
ABC News and ABC 7.30

TED (Technology, Entertainment, Design) is a global set of conferences owned by the private non-profit Sapling Foundation, under the slogan: "Ideas Worth Spreading".TED was founded in 1984 as a one-off event. TED addresses a wide range of topics within the research
and practice of science and culture, often through storytelling. The speakers are given a maximum of 18 minutes to present their ideas in the most innovative and engaging ways they can. As of April 2014, over 1,700 talks are available free online.By January 2009 they had been viewed 50 million times. In June 2011, the viewing figure stood at more than 500 million, and on Tuesday, November 13, 2012, TED Talks had been watched one billion times worldwide.This posting has selected a range of TED talks that relate to the geographical/spatial world and are well worth watching. As short talks they are ideal as stimulus material for the classroom.

* Changing the world, one map at a timeMaps have always been a source of fascination and intrigue. Today's
maps, however, can also help to save lives during disasters, document
human rights abuses and monitor elections in countries under repressive
rule. This presentation explains how today's live maps can combine
crowds and clouds to drive social change. The presenter, Patrick Meier is
Director of Crisis Mapping at Ushahidi—a non-profit technology company
voted by MIT's Technology Review as one of the 50 most innovative
companies in the world alongside Facebook. Patrick is also co-founder of
the International Network of Crisis Mappers and previously co-directed
Harvard University's Program on Crisis Mapping and Early Warning."I want to remind this community that geospatial skills can be used to help others. Want to see geographic knowledge and geospatial skills in action? Crowd-sourced mapping is increasingly an important resource during an emergency. Poorer
places are often not as well mapped out by the commercial cartographic
organizations and these are oftentimes the places that are hardest hit
by natural disasters. Relief agencies depend on mapping platforms to
handle the logistics of administering aid and assessing the extent of
the damage and rely on these crowd-sourced data sets made by people like
you and me" * The best stats you've ever see: Hans Rosling You've never seen data presented like this. With the drama and urgency
of a sportscaster, statistics guru Hans Rosling debunks myths about the
so-called "developing world."
* Global population growth: box by box

The world's population will grow to 9 billion over the next 50 years --
and only by raising the living standards of the poorest can we check
population growth. This is the paradoxical answer that Hans Rosling
unveils at TED@Cannes using colorful new data display technology.

Map
designer Aris Venetikidis is fascinated by the maps we draw in our minds
as we move around a city -- less like street maps, more like schematics
or wiring diagrams, abstract images of relationships between places.
How can we learn from these mental maps to make better real ones? As a
test case, he remakes the notorious Dublin bus map.

Many people think the lines on the map no longer matter, but Parag
Khanna says they do. Using maps of the past and present, he explains the
root causes of border conflicts worldwide and proposes simple yet
cunning solutions for each.* For more wonder: Rewild the World

Wolves were once native to the US' Yellowstone National Park — until
hunting wiped them out. But when, in 1995, the wolves began to come back
(thanks to an aggressive management program), something interesting
happened: the rest of the park began to find a new, more healthful
balance. In a bold thought experiment, George Monbiot imagines a wilder
world in which humans work to restore the complex, lost natural food
chains that once surrounded us.

If politics and the economy are the world's day, then the Internet and
its subculture are its night. In the latest issue of Planets Critic
Magazine, pundit Tsunehiro Uno rewrites the relationship between
politics and literature, equating society and the individual with day
and night in a ringing declaration. Planets began publishing in 2005.
From subcultures to politics, Tsunehiro has discussed various topics
with the people of the times.* Overpopulation, the facts: the problem no one will discuss

Actress Alexandra Paul breaks the silence on one of the most taboo
subjects of our time: human overpopulation and how to resolve the crisis
that is adding 220,000 more people to the planet every day. In this
fact filled talk, Alexandra discusses the overpopulation problems of 7
billion humans multiplying at a rate of 1 billion more people every 12
years and offers a simple solution: Transform negative cultural
attitudes about the Only Child, and celebrate the short and long term
benefits of small families. Alexandra reminds us that coercion
in any form is not the answer to changing cultural and biological norms.
Instead, rewiring our biology through strong cultural messaging,
education of girls and empowerment of women are the solutions to
stopping the current momentum towards 10 billion people on the planet in
40 years. Alexandra emphasizes that because each American born
uses so many more resources than someone from a developing country, it
is equally important that wealthy countries have small families. She
discusses the economic tradeoffs of a smaller population in a world
where capitalism reigns: because the capitalist system depends upon more
and more consumers, there are strong forces at work to keep the numbers
of people on earth growing. But at what expense?And since human numbers cannot keep getting larger forever, at what point will we change our ways? When it is too late? Most
controversially, Alexandra believes that, if humans are to survive on
this planet, the ideal family has one child and the ideal number of
people on earth is 2 billion. "If that is too radical, then it is time
for radicalism. Too much is at stake to be polite." This talk is full of
overpopulation facts.* Your health depends upon where you live

Where you live: It impacts your health as much as diet and genes do, but
it's not part of your medical records. At TEDMED, Bill Davenhall shows
how overlooked government geo-data (from local heart-attack rates to
toxic dumpsite info) can mesh with mobile GPS apps to keep doctors in
the loop. Call it "geo-medicine.* Dreams from endangered cultures

With stunning photos and stories, National Geographic Explorer Wade
Davis celebrates the extraordinary diversity of the world's indigenous
cultures, which are disappearing from the planet at an alarming rate.
* Food shaped our cities

Every day, in a city the size of London, 30 million meals are served.
But where does all the food come from? Architect Carolyn Steel discusses
the daily miracle of feeding a city, and shows how ancient food routes
shaped the modern world.
* The worldwide web of belief and ritual

Anthropologist Wade Davis muses on the worldwide web of belief and
ritual that makes us human. He shares breathtaking photos and stories of
the Elder Brothers, a group of Sierra Nevada Indians whose spiritual
practice holds the world in balance* Mapping historyIn a fun and interesting talk,
researcher and engineer Frederic Kaplan shows off the Venice Time
Machine, a project to digitize 80 kilometers of books to create a
historical and geographical simulation of Venice across 1000 years. * Ecology from the air

What are our forests really made of? From the air, ecologist Greg Asner
uses a spectrometer and high-powered lasers to map nature in meticulous
kaleidoscopic 3D detail — what he calls “a very high-tech accounting
system” of carbon. In this fascinating talk, Asner gives a clear
message: To save our ecosystems, we need more data, gathered in new
ways.
Not geography but just inspirational - worth a watch - A philosophy for a happy life.

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Who am I?

I have taught history, geography and civics and citizenship in the South Australian education system since 1976. I have been actively involved in the promotion of geography and history over the years, in particular the use of spatial technology in schools. I am a Past Chair of the Australian Geography Teachers' Association (Chair 2008-13) and Immediate Past President of the Australian Alliance of Associations in Education (2013-present). During the development of the Australian Curriculum: Geography I was a member of the ACARA Advisory Panel (2009-2013) and Executive Director of the ESA GeogSpace project. From 2007-2011 and in 2015 I was the Manager for the Humanities and Social Sciences (HaSS) in the South Australian Department for Education and Child Development (DECD). Presently I am a Teaching Academic in HaSS Education at the University of South Australia and the Manager for the Premier's ANZAC Spirit School Prize in DECD.